1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method for generating an interleaf image for separating printed sheets in a case where an edited job is printed as images on print sheets, an image output system for printing an interleaf image on a print sheet, and a program for generating an interleaf image and outputting the generated interleaf image to a print sheet.
2. Description of the Related Art
In recent years, the widespread use of DTP (DeskTop Publishing) and CTP (Computer To Plate) technologies or the progress of printing machines has allowed image output systems to operate according to a digital printing process work flow as a whole thereby to produce a small number of prints on a POD (Print On Demand) basis, for example. Such an image output system can carry out an efficient printing process by setting print sheets (print mediums) of the same type of paper in a printing machine and successively printing a plurality of print lots on the print sheets.
In a case where a plurality of print lots are successively printed on print sheets to produce stacked prints, it is occasionally unable to easily distinguish between a stack of prints from a previously printed print lot and a stack of prints from a subsequently printed print lot. Image output systems designed to solve such a problem make it possible to easily distinguish between stacks of prints from two different print lots by inserting an interleaf between those stacks of prints in a case where the stacks of prints from the two different print lots are stacked together (see, for example, Japanese Laid-Open Patent Publication No. 2007-028098 and Japanese Laid-Open Patent Publication No. 2010-111078). Specifically, since the stacked prints with the interleaf inserted therebetween have different colors on their side edges from the color of the side edge of the interleaf, if the stacks of prints are seen in side elevation, it is possible to easily distinguish the stacks of prints from each other based on the inserted position of the interleaf.